/*
 * Copyright 2007 ZXing authors
 * 
 * Modified by John Ahlroos 2011
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package fi.jasoft.qrcode.zxing;

/**
 * <p>
 * See ISO 18004:2006, 6.4.1, Tables 2 and 3. This enum encapsulates the various
 * modes in which data can be encoded to bits in the QR code standard.
 * </p>
 * 
 * @author Sean Owen
 * @author John Ahlroos
 */
public final class Mode {

    // No, we can't use an enum here. J2ME doesn't support it.

    public static final Mode TERMINATOR = new Mode(new int[] { 0, 0, 0 }, 0x00,
            "TERMINATOR"); // Not really a mode...
    public static final Mode NUMERIC = new Mode(new int[] { 10, 12, 14 }, 0x01,
            "NUMERIC");
    public static final Mode ALPHANUMERIC = new Mode(new int[] { 9, 11, 13 },
            0x02, "ALPHANUMERIC");
    public static final Mode STRUCTURED_APPEND = new Mode(
            new int[] { 0, 0, 0 }, 0x03, "STRUCTURED_APPEND"); // Not supported
    public static final Mode BYTE = new Mode(new int[] { 8, 16, 16 }, 0x04,
            "BYTE");
    public static final Mode ECI = new Mode(0x07, "ECI"); // character counts
                                                          // don't apply
    public static final Mode KANJI = new Mode(new int[] { 8, 10, 12 }, 0x08,
            "KANJI");
    public static final Mode FNC1_FIRST_POSITION = new Mode(0x05,
            "FNC1_FIRST_POSITION");
    public static final Mode FNC1_SECOND_POSITION = new Mode(0x09,
            "FNC1_SECOND_POSITION");

    private final int[] characterCountBitsForVersions;
    private final int bits;
    private final String name;

    private Mode(int bits, String name) {
        characterCountBitsForVersions = null;
        this.bits = bits;
        this.name = name;
    }

    private Mode(int[] characterCountBitsForVersions, int bits, String name) {
        this.characterCountBitsForVersions = new int[characterCountBitsForVersions.length];
        System.arraycopy(characterCountBitsForVersions, 0,
                this.characterCountBitsForVersions, 0,
                characterCountBitsForVersions.length);
        this.bits = bits;
        this.name = name;
    }

    /**
     * @param bits
     *            four bits encoding a QR Code data mode
     * @return {@link Mode} encoded by these bits
     * @throws IllegalArgumentException
     *             if bits do not correspond to a known mode
     */
    public static Mode forBits(int bits) {
        switch (bits) {
        case 0x0:
            return TERMINATOR;
        case 0x1:
            return NUMERIC;
        case 0x2:
            return ALPHANUMERIC;
        case 0x3:
            return STRUCTURED_APPEND;
        case 0x4:
            return BYTE;
        case 0x5:
            return FNC1_FIRST_POSITION;
        case 0x7:
            return ECI;
        case 0x8:
            return KANJI;
        case 0x9:
            return FNC1_SECOND_POSITION;
        default:
            throw new IllegalArgumentException();
        }
    }

    /**
     * @param version
     *            version in question
     * @return number of bits used, in this QR Code symbol {@link Version}, to
     *         encode the count of characters that will follow encoded in this
     *         {@link Mode}
     */
    public int getCharacterCountBits(Version version) {
        if (characterCountBitsForVersions == null) {
            throw new IllegalArgumentException(
                    "Character count doesn't apply to this mode");
        }
        int number = version.getVersionNumber();
        int offset;
        if (number <= 9) {
            offset = 0;
        } else if (number <= 26) {
            offset = 1;
        } else {
            offset = 2;
        }
        return characterCountBitsForVersions[offset];
    }

    public int getBits() {
        return bits;
    }

    public String getName() {
        return name;
    }

    public String toString() {
        return name;
    }

}
